Natural log wall constructions typically utilize whole or solid logs with the outer bark and inner bark (cork cambium and secondary phloem) removed, leaving the sapwood layer of the log exposed. Although solid log buildings are quite authentic, they are often times unstable, difficult to install, and costly to maintain. The instability of larger logs manifests itself in shrinking, checking, twisting, warping, and inconsistent settling due to different drying patterns in the logs. Also, gable construction may require modification or additional structure to compensate for the instability of the solid logs and to provide a stable structural roof system as the building compresses and settles. Further, the weight of solid logs may require larger footings or other additional structural support. Additionally, the increased growth life of larger-diameter solid logs may affect the availability of the desired logs for construction. In order to maintain and preserve these logs a stain or varnish is often applied to the logs resulting in a distinctly recognizable surface.
Over the years many attempts have been made to provide a contoured siding material that simulates a solid debarked log wall construction. Generally, various sidings have previously been described to cover the interior or exterior walls of a budding which attempt to simulate a solid log wall construction.
One known prior siding system includes an exterior surface that attempts to simulate the exterior of the sapwood of a natural log by utilizing a veneer that is bent to simulate a curved exterior portion of a log. The veneer is typically thin and smooth, lacking the appearance of a debarked log surface. Veneers are commonly of the peeled, sliced, or sawn type (typically ⅛ inch thick) or may comprise a two layer veneer consisting of a sawn or sliced veneer and a rotary peeled veneer having a typical combined thickness of ¼ inch. This veneer ‘skin’ is laminated to an expanded polystyrene core, which in turn is laminated to a piece of oriented strand board. An additional film forming stain may be applied to the veneer to mitigate the effects of rain on the veneer. This type of veneer siding is described further in U.S. Pat. No. 5,271,878A.
Once a veneer siding of this type is applied to an exterior wall it has been observed that the log veneer siding surface temperatures may reach 165° F. Additionally, the thin veneer layer may be subjected to significant temperature swings. These changes in temperature may lead to premature degradation of the veneer layer including feathering or checking of the veneer. A further disadvantage of veneer siding is a limitation in available widths of the veneer. Manufacturing constraints typically limit the maximum width of a veneer resulting in a maximum length of siding in the range of 98 inches without a seam. Each seam or short length of siding may diminish the energy integrity of the building envelope and may increase a potential for moisture migration.
Other prior devices describe techniques for creating the appearance of a whole or complete log that require sides, a support positioned between the two sides to hold the sides in a spaced relation and insulation filling a void created between the two sides. The upper and lower portions of the simulated log include gaps or openings in the top and bottom sides of the log. Representative examples of these systems are described in U.S. Pat. Nos. 4,433,519A, 3,377,758 and 5,782,046A. Although the described “logs” apparently stack together to form a structural load-bearing wall, the supports are required to align vertically which may prove impractical during installation in the field.